Center Height Mounted Stop Lamps (CHMSL) have been have been standard equipment on all new passenger cars sold in the United States since model year 1996, As required by US Federal Law. The same requirement has applied to light trucks since model year 1994. Consisting of a light mounted above, or just inside, the back glass the CHMSL is designed to provide unambiguous warning that the vehicle is slowing down or stopping, from a source above the level of the vehicle's taillights.
Passenger vehicles often have a CHMSL located inside the vehicle's rear glass, but light truck designs generally locate the CHMSL above the rear glass, mounted in an aperture extending through the truck body sheet metal. Truck owners, however, made desire to add auxiliary lighting to the CHMSL to provide, for example, additional turn indicator lights. Conventionally, that process requires additional holes to be formed in the vehicle sheet metal, an operation that not only damages the vehicle body but creates an entry point for water intrusion. That damage may also negatively impact the resale price of the vehicle.
Therefore, a need exists for an assembly for mounting auxiliary lighting on a vehicle such as a light truck, without requiring additional holes in the vehicle body. Such an assembly would maintain the integrity of the vehicle body as well as ensuring that the potential for water penetration was minimized.